Abstract

Ovulation-inducing factor (OIF) is a protein present in llama seminal plasma that has recently been identified as β-Nerve Growth Factor (NGF) and it induces not only a high rate of ovulation but also appears to have luteotrophic properties in this species. A 2-by-2 experimental design was used to determine the effect of treatments (OIF/NGF vs GnRH) and categories of preovulatory follicle diameter (7-10 vs >10 mm) on ovulation rate, CL diameter and function in llamas. Llamas (n = 32 llamas per group) were randomly assigned to receive an intramuscular dose of: a) 1 mg purified OIF/NGF in the presence of a follicle of 7-10 mm in diameter; b) 50 ug of GnRH in the presence of a follicle of 7-10 mm in diameter; c) 1 mg purified OIF/NGF in the presence of a follicle > 10 mm in diameter; d) 50 ug of GnRH in the presence of a follicle > 10 mm in diameter. Llamas were examined by ultrasonography every 12 hours from treatment to Day 2 (Day 0 = treatment) to detect ovulation, and again on Day 8 to determine CL diameter. Ovulation rates did not differ among groups. There was an effect of preovulatory follicle size on Corpus luteum diameter at Day 8 (P < 0.001), however plasma progesterone concentration (n = 15/per group) was higher (P < 0.05) in the OIF/NGF- than that of the GnRH- treated group by the same day. We conclude that OIF/NGF treatment enhances CL function regardless preovulatory follicle size at the time of treatment Ovulation-inducing factor (OIF/NGF) from seminal plasma origin enhances Corpus Luteum function in llamas regardless the preovulatory follicle diameter. Available from: https://www.researchgate.net/publication/262879834_Ovulation-inducing_factor_OIFNGF_from_seminal_plasma_origin_enhances_Corpus_Luteum_function_in_llamas_regardless_the_preovulatory_follicle_diameter [accessed May 3, 2017].